Issue

The xhtml:link is not returned in the Entity object in order to determine alternative languages.

Fix

Check for <xhtml:link and return items as Vec<String>.

Hey @svmk

I was testing this crate and tried few public sitemaps like:

• https://www.google.com/sitemap.xml - parses just fine
• https://enterprise.google.com/sitemap.xml - fails to parse, the odd thing that there are no errors whatsoever

Maybe you will now the problem straight away?

Google complains about <sitemapindex> tag which should declare a namespace.
Seems to be a follow-up to #5.

Your Sitemap or Sitemap index file doesn't declare the expected namespace: http://www.sitemaps.org/schemas/sitemap/0.9

I'm trying to use this with error-chain, but it expects any error to implement std::error:Error:

error[E0599]: no method named `cause` found for type `&sitemap::Error` in the current scope
  --> src/actions/errors.rs:43:1
   |
43 | / error_chain! {
44 | |     foreign_links {
45 | |         Bcrypt(::bcrypt::BcryptError);
46 | |         Db(::diesel::result::Error);
...  |
67 | |     }
68 | | }
   | |_^